The production of one enantiomeric form of a chiral compound is often required in the pharmaceutical and other chemical industries and the desired enantiomer is obtained via resolution of its racemate. In such a process it is essential from the economic point of view to convert the unwanted enantiomer back to the racemic form and recycled.
In the racemization step, ruthenium complexes such as [(p-cymene)RuCl2]2 and (η5-Ph4C4CO)2H(μ-H)(CO)4Ru2 (Shvo catalyst) are used as a catalyst. However, the ruthenium cymene complex exhibits a slow racemization reaction at room temperature, and Shvo catalyst which exists in the form of a dimer must be activated at a high temperature and it also requires the use of a hydrogen-transfer agent, e.g., the corresponding ketone to the alcohol in case a chiral alcohol is to be racemized (Y. Shvo et al, Organometallics, 8, 162, 1989).